My family is moving from Colorado to Alaska which is approximately 60 hours. We plan to stop each night and sleep at a hotel. This will allow us to set up a mini aquarium for him through the night. I understand we may upset him with switching the daylight hours, but at least he will be having an opportunity to sun bathe. I plan to transport him in a sturdy cardboard box with shredded newspaper. I am looking for suggestions on a heating pad for him. Also, if anyone has anymore information or advice to help make our turtle more comfortable through the journey, I would really appreciate it.
Don't worry much about it, a few days without basking or swimming won't really affect his health. It will be uncomfortable, that's true, but it will be the same for the whole family.
Cardboard is not a good idea, he will tear through it in no time, and you will have to hunt him inside the car (you don't want to do that, believe me).
Use a plastic food container, punching a few holes in the cover (smooth them, he will try to push his head through there and may hurt his skin). Cover the bottom of the container with a wet towel and place the whole contraption in the car floor. The lower it is, the less oscillation when the car moves, and dimmer light will help soothe him. Just make sure the lid is firmly secured (again, terrapin on the loose in a car is something you don't like)
No matter what you do, this is going to be uncomfortable and stressful for him. If he likes you handling him, you may want to cuddle him at every stop.
That's how I transport my yellow bellied sliders and so far so good. My longer trip was Madrid to London, just one day so significantly shorter than yours.